An example of using a liquid discharge head that discharges a liquid is an ink jet recording head for use in an ink jet recording method whereby ink is discharged onto a recording target medium to perform recording.
The ink jet recording head (recording head) has a substrate that at least includes: a plurality of discharge ports from which ink is discharged; a flow channel communicated with each discharge port; a supply port for supplying the ink to the flow channel; and an energy generating element for applying discharge energy to the ink in the flow channel. The recording head further has a support member that supports the substrate, an ink supply channel formation member that supplies the ink to the substrate, and the like. As the substrate, a substrate made of Si (silicon) is typically used. The ink supply channel formation member is made of a plastic or the like.
In such a recording head, there is conventionally the case where, due to a difference in linear expansion coefficient between a discharge element substrate provided with the energy generating element for discharging the liquid from the discharge port and an ink supply member for holding the liquid, a stress to a joint interface increases and as a result the discharge element substrate suffers warpage or contortion.
In such a case, a thermal stress occurs on the joint interface between the discharge element substrate and the ink supply member due to a temperature rise during recording and the like and causes the discharge element substrate to become deformed, as a result of which a recorded image can be affected.
To solve the above-mentioned problem, U.S. Pat. No. 6,257,703 describes a structure in which a support member having an equal linear expansion coefficient to the discharge element substrate is interposed between the discharge element substrate and the ink supply member. Moreover, Japanese Patent Application Laid-Open No. 2007-276156 discloses a method of molding a support member having an equal linear expansion coefficient to the discharge element substrate, integrally with the ink supply member.
However, required properties are different between a material used for the ink supply member and a material used for the support member. Therefore, even when the support member and the ink supply member are integrally formed, a favorable joint state cannot be attained, and there is a possibility that peeling or the like occurs between the support member and the supply member after molding and causes a decrease in liquid tightness. Hence there is a problem of needing to attain a state where the support member and the ink supply member are joined together with an extremely high affinity.